GdkScreen size-changed and gdk_monitor_get_workarea problem

["Sebastian Geiger (Lanoxx)" <lanoxx gmx net>]

Hi Gtk developers,

I am experiencing a wired issue and I am wondering if I am using the API
in a wrong way of if there is a problem with Gtk.

I have registered a callback to the "size-changed" signal like so:

    g_signal_connect (screen, "size-changed",
                      G_CALLBACK(monitor_changed_cb), data);

In the monitor_changed_cb function I am first calling:

gdk_display_get_monitor_at_point and then gdk_monitor_get_workarea.

My implementation seemed to work when the monitor size changes to
a smaller size, but not when changing to a bigger size.

I am testing this in VM. To test my implementation I changed the monitor
resolution a couple of time via Gnome Settings.

I start my app with a resolution of 1400x1050.

First I change to 1024x786 and my signal handler correctly reports the
new monitor size minus panel area.

Then I change back to 1400x1050 and my signal handler instead reports
1024x720 (previous size minus panel area).

Now I change to 1920x1080 and my signal handler reports 1400x1002
(previous size minus panel area).

I guess its more likely that I am doing something wrong, rather than
that there is a bug in Gtk. So, is there something I should do in my
signal handler before I call gdk_monitor_get_workarea to get the correct
values?

Best Regards
Sebastian